Dyslexia is characterized by trouble with reading despite normal intelligence and may affect different individuals to varying degrees. Dyslexic individuals may have difficulties in reading words, writing words, spelling words, “sounding out” words in their head, pronouncing words aloud, and/or understanding what the individual reads. Dyslexia may be caused by both genetic and environmental factors and is commonly first diagnosed at school. The onset of dyslexia may also take place during adulthood following traumatic brain injury, stroke, or dementia.